Index: test/Common/NetTopologySuite.Extensions.Tests/Geometries/GeometryHelperTest.cs
===================================================================
diff -u -r5fc71a385897af92ccb092f2f969b5709afab85a -r65f2e7d6ac377e64d885b6379ba3553a2deef981
--- test/Common/NetTopologySuite.Extensions.Tests/Geometries/GeometryHelperTest.cs	(.../GeometryHelperTest.cs)	(revision 5fc71a385897af92ccb092f2f969b5709afab85a)
+++ test/Common/NetTopologySuite.Extensions.Tests/Geometries/GeometryHelperTest.cs	(.../GeometryHelperTest.cs)	(revision 65f2e7d6ac377e64d885b6379ba3553a2deef981)
@@ -345,19 +345,17 @@
                 new Coordinate(0, 0),
                 new Coordinate(10, 0)
             });
-            Coordinate nullCoordinate = null;
-            Point nullGeometry = null;
 
             var distance = GeometryHelper.Distance(null, new Coordinate(0, 0));
             Assert.AreEqual(double.MaxValue, distance);
 
-            distance = GeometryHelper.Distance(lineString, nullCoordinate);
+            distance = GeometryHelper.Distance(lineString, (Coordinate) null);
             Assert.AreEqual(double.MaxValue, distance);
 
             distance = GeometryHelper.Distance(null, new Point(0, 0));
             Assert.AreEqual(double.MaxValue, distance);
 
-            distance = GeometryHelper.Distance(lineString, nullGeometry);
+            distance = GeometryHelper.Distance(lineString, (Point) null);
             Assert.AreEqual(double.MaxValue, distance);
         }